code: def unhighlighted(self, source):
      raise AssertionError("should highlight %r" % source)
  
file_path: sphinx/tests/test_highlighting.py
imports: from unittest import mock
  from pygments.formatters.html import HtmlFormatter
  from pygments.lexer import RegexLexer
  from pygments.token import Name, Text
  from sphinx.highlighting import PygmentsBridge
label_desc: Use image node_id 1 for calling the ComplainOnUnhighlighted obj's underlying member method code with example usage: obj.unhighlighted(source) without return types